They got many strange plants in Laos over the last 5 years, including a plant that looks like a druryi for the leaves and has a flower with a very wide black mark on the dorsal. They had a lot of funny insigne types as well. This group of plant being less interesting to many people than the parvisepalum, no one cared about describing or mentioning those plants.
It is difficult to ID a species using only a small photo unless the species is very, very distinctive. I'd recommend contacting a noted Paph taxonomist, there are a few hanging around these slipper orchid forums. They may want you to cut the flower off and send it to them and they may charge you a small fee, but at least you'd then get a reliable ID from an expert.
I suspect this Paph is Paph insigne var. albo marginata. The characteristic that distinguishes this variety from other insigne is that no spots or markings spill over onto the white dorsal margin. But as I said above, any ID done by a small pic over the web would be tenuous at best. I'd send ot to a taxonomist and get it identified properly and reliably.
You can buy them on the Bangkok Jatujak Market, they collect a lot of them for pot-plant. Ask the paphs sellers if they can sell to you one or two boxes...
Chiang Mai has many plants available as well. I have seen boxes and boxes of them, you can ask any Thai orchid grower, they know about that plant. The price is so low and the quantities available from the local growers ( that you will most likely never meet...) so huge that no one dare to offer or export them. There are some plants here and there outside of Thailand however. It is not a really fast growing species.
The plant pictured is most likely one of those strange insigne types. In Laos they even have Paph. viniferum, I have seen some pictures from a collector, he had dozens of them. The original vinicolor most likely come from Laos. Most Thai growers import from Laos since decades, because the labor cost is so cheap. One 30kg box of Lao paph dianthum cost only 50$ (and most of the dianthum available now are coming from Laos), makes a lot of plants.